The unlikely chance the Islanders make an early move to Brooklyn is now at least officially a chance.

At Friday’s detailed announcement of Bruce Ratner’s winning bid to redevelop the Nassau Coliseum site, both Ratner and Nassau County Executive Ed Mangano said there is a possibility the Islanders will play their home games at Barclays Center in Brooklyn before their lease expires on Long Island after the 2014-15 season.

“I wouldn’t foreclose anything,” Mangano told The Post. “But as Bruce said, and I agree, it’s much more likely than not that the Islanders will play another two seasons here.”

Once the Islanders agreed to move the franchise to Brooklyn, the talk began of how early they could leave. Now that Ratner and the owners of Barclays Center are the ones developing the Coliseum site, that process could be expedited by the fact the team’s departure can seamlessly coincide with the start of construction.

The only problems arise with the fact construction plans have to be drawn up, which can take up to a year, and then have to be approved by the Town of Hempstead — which, as Islanders’ owner Charles Wang can attest, can be a mighty arduous task.

“Someone is going to have to show me a construction schedule that is ready to get a shovel in the ground,” Mangano said. “I really think about what’s best for all the taxpayers at large and what’s best for the project to succeed. Right now, the time frame pretty well lines up with the Islanders staying here another two years.”

Surprisingly, Mangano said no one has approached him in discussions about moving the team early. Yet he didn’t award Ratner the development bid until Thursday afternoon, so it’s only now they can begin drawing up plans.

“I still think probably it will be two years,” Ratner said cautiously. “I don’t want to say 100 percent, but probably. There’s a chance [the team moves early], but I think less likely.”

Part of Ratner’s proposal — which was leaps and bounds more lucrative for the county than the rival proposal from Madison Square Garden — was to have the Islanders play up to six home games a year back at the revitalized (and downsized) Coliseum once construction is completed. That would have to be approved by the NHL, which might not take too fondly to one of its teams playing home games in an arena set to hold around 12,000.

Although Ratner said he hasn’t had any discussion yet with the league about the matter, when asked if there was any fear they might shoot the idea down, he simply said, “No.”

*

Ratner also said the Islanders’ AHL affiliate, the Bridgeport Sound Tigers, will become a main tenant of the new Coliseum once it’s completed. … The plan also entails bringing college basketball to the arena (for that reason, Kentucky’ John Calipari spoke at yesterday’s news conference), as well as boxing and possibly an Arena football league team.

Along the current time frame, including the Islanders playing through the 2014-15 season and a 15-18 month construction period, that would make the Sounds Tigers’ first year on Long Island 2017-18.